Gtk# TreeView, not using certail columns for non-leaf nodes?-CodePudding

The code below shows the second column for non-leaf nodes. But that is not what I wanted. Can I make only leaf nodes have the second column?

        var languages = new TreeViewColumn();
        languages.Title = "Programming languages";

        var efficiency = new TreeViewColumn();
        efficiency.Title = "Efficiency";

        var cell = new CellRendererText();
        languages.PackStart(cell, true);
        languages.AddAttribute(cell, "text", 0);

        var cell2 = new CellRendererProgress();
        efficiency.PackStart(cell2, true);
        efficiency.AddAttribute(cell2, "value", 1);

        var treestore = new TreeStore(typeof(string), typeof(int));

        var iter = treestore.AppendValues("scripting languages");
        treestore.AppendValues(iter, "Python", 10);

        iter = treestore.AppendValues("compiling");
        treestore.AppendValues(iter, "C#", 20);

        tree.AppendColumn(languages);
        tree.AppendColumn(efficiency);
        tree.Model = treestore;
        tree.ExpandAll();

CodePudding user response：

After tens of minutes of searching, trial & error (because Gtk# lacks any documentation and there are not many examples on line), I got it working. I'm not sure if this is the most efficient way, but at least it is working. If someone finds a better way, please post it; I will mark that as the answer.

The hint was

CodePudding user response：

I haven't worked with "C#" in a while, but researching how to hide a specific renderer cell, I came across the following link.

"https://stackoverflow.com/questions/35057446/python3-gtk3-how-to-hide-a-cell-of-a-row"

The information to build on here is as follows:

Include a hidden column in your tree store that can hold a boolean value.
Add a "visibility" attribute to the progress bar cell that references the value that will be placed within hidden column cell for each row.
For those cells that should display the progress bar, set the associated hidden column cell to a value of "TRUE".
For those cells that should not display the progress bar, set the associated hidden column cell to a value of "FALSE".

Using this information, I built a sample program that had a tree view with one of the columns being a progress bar. I won't list out the whole program here, but I will paste in some of the key bits. I realize this will be C code, but one should be able to interpret what the equivalent code would be in C#.

First off, I define the columns that I want in the tree view (two viewable columns, and a hidden column).

enum
{
    COLUMN = 0,
    PROG = 1,
    VIS = 2,
    N_COLS          /* Used as a terminator/counter */
}

Then, I create a view and model. Following is a snippet of the code to set up the cell renderers for the two visible columns.

renderer    = gtk_cell_renderer_text_new();
renderer2   = gtk_cell_renderer_progress_new();

gtk_tree_view_column_set_title(col, "Programming Languages");
gtk_tree_view_append_column(GTK_TREE_VIEW(view), col);
gtk_tree_view_column_pack_start(col, renderer, TRUE);    /* This will be visible on the tree view */
gtk_tree_view_column_add_attribute(col, renderer, "text", COLUMN);

gtk_tree_view_column_set_title(col2, "Percentage");
gtk_tree_view_append_column(GTK_TREE_VIEW(view), col2);
gtk_tree_view_column_pack_start(col2, renderer2, TRUE);  /* This will be visible on the tree view */
gtk_tree_view_column_add_attribute(col2, renderer2, "value", PROG);
gtk_tree_view_column_add_attribute(col2, renderer2, "visible", VIS);

The last line of code above is the additional bit I think you are looking for to control the visibility of the progress bar cell..

Next, I define that the tree view will have three columns (the last one will be hidden).

treestore = gtk_tree_store_new(NUM_COLS, G_TYPE_STRING, G_TYPE_INT, G_TYPE_BOOLEAN);

gtk_tree_store_append(treestore, &toplevel, NULL);
gtk_tree_store_set(treestore, &toplevel, COLUMN, "Scripting Languages", VIS, FALSE, -1);
gtk_tree_store_append(treestore, &child, &toplevel);
gtk_tree_store_set(treestore, &child, COLUMN, "Python", PROG, 62, VIS, TRUE, -1);
/* And so forth for other rows */

The result of this produces a tree view with conditioned display of the progress bar cell.

As noted, I built this example in C, but the method of adding a visibility attribute to the progress bar cell and making its visibility dependent upon the value in a hidden boolean cell/column should be easily interpreted to C#.